I just released VueScan 6.6.4 for Windows, Mac OS and Linux.
It can be downloaded from:
What's new in version 6.6.4
* Fixed problem with some very dark negatives
* Fixed problem with Agfa Arcus and other Acer-manufactured
scanners not being recognized occasionally
* Increased exposure time for long exposure on Minolta
Scan Dual, Scan Speed, Scan Elite and Scan Multi.
* Fixed some rare problems with cleaning images
* Fixed problem with eject after scan with Scan Dual II